Haploinsufficiency of TNFAIP3 (A20) by germline mutation is involved in autoimmune lymphoproliferative syndrome.

Background Autoimmune diseases in children are rare and can be difficult to diagnose. Autoimmune lymphoproliferative syndrome (ALPS) is a well-characterized pediatric autoimmune disease caused by mutations in genes associated with the FAS-dependent apoptosis pathway. In addition, various genetic alterations are associated with the ALPS-like phenotype. Objective The aim of the present study was to elucidate the genetic cause of the ALPS-like phenotype. Methods Candidate genes associated with the ALPS-like phenotype were screened by using whole-exome sequencing. The functional effect of the identified mutations was examined by analyzing the activity of related signaling pathways. Results A de novo heterozygous frameshift mutation of TNF-α–induced protein 3 (TNFAIP3, A20), a negative regulator of the nuclear factor κB pathway, was identified in one of the patients exhibiting the ALPS-like phenotype. Increased activity of the nuclear factor κB pathway was associated with haploinsufficiency of TNFAIP3 (A20). Conclusion Haploinsufficiency of TNFAIP3 (A20) by a germline heterozygous mutation leads to the ALPS phenotype. [ABSTRACT FROM AUTHOR]